"er humör"? Are we trying to be super formal, or should this have been translated as second person plural by default?
Without context, it's impossible to tell - but I'd also default to assuming the plural you was meant.
Also, please note that using er in a formal manner isn't really considered "super formal" in Swedish.
True about "super formal", it's just strange to encounter "er" in tålspråk definitely, and unless I was addressing the king, I probably wouldn't use it, even in writing.